The DrHylo package

DrHylo is a tool for deriving hylomorphisms from a restricted Haskell syntax. It is based on the algorithm first presented in the paper Deriving Structural Hylomorphisms From Recursive Definitions at ICFP'96 by Hu, Iwasaki, and Takeichi.
The generated code can be run with Pointless Haskell (http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pointless-haskell), allowing the visualization of the recursion trees of Haskell functions.